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Copper vs. Aluminum Solar Cables: How to Choose the Best Material for PV System

Updated: Mar 9, 2023


When designing a photovoltaic (PV) system, one of the most important decisions is to choose the right solar cable material. Copper and aluminum are the two most common materials used for solar cables, and each has its own unique properties and advantages.


In this blog post, we’ll compare copper and aluminum solar cables based on their electrical and mechanical properties, as well as their cost-effectiveness and environmental impact. We’ll also give you some tips on deciding which material is best suited for your PV system.


Copper vs. Aluminum Solar Cables:



Electrical Properties of Copper vs. Aluminum Solar Cables

1. Electrical conductivity

One of the main factors to consider when choosing a solar cable material is its electrical conductivity, which measures how well it can carry electric current. The higher the conductivity, the lower the resistance and the power loss of the cable.


Copper has a higher electrical conductivity than aluminum, which means it can carry more current per unit length than aluminum of the same diameter. This also means that copper cables can be thinner than aluminum cables for a given current rating, which reduces their weight and installation costs.


However, aluminum has a lower density than copper, which means it can carry more current per unit weight than copper of the same diameter. This also means that aluminum cables can be thicker than copper cables for a given current rating, which increases their flexibility and durability.


2. Thermal expansion coefficient

Another factor to consider is the thermal expansion coefficient, which measures how much a material expands or contracts when heated or cooled. The higher the coefficient, the more material changes its shape or size due to temperature changes.

Aluminum has a higher thermal expansion coefficient than copper, which means it expands or contracts more when exposed to high temperatures or cold weather. This can cause loose connections or cracks in aluminum cables over time, especially if they are not properly installed or maintained.


Copper has a lower thermal expansion coefficient than aluminum, which means it maintains its shape or size better when exposed to temperature changes. This makes copper cables more stable and reliable over time, especially if they are properly installed or maintained.



Mechanical Properties of Copper vs. Aluminum Solar Cables

1. Mechanical strength

Another factor to consider when choosing a solar cable material is its mechanical strength, which measures how well it can resist deformation or damage under stress. The higher the strength, the more material can withstand tension, compression, bending, twisting, or impact forces.

Pressure Test for Solar Cables
Pressure Test for Solar Cables

Copper has a higher mechanical strength than aluminum, which means it can resist deformation or damage better under stress than aluminum of the same diameter. This also means that copper cables can handle more load without breaking or sagging than aluminum cables.


However, aluminum has a higher ductility than copper, which means it can deform more easily without cracking or breaking under stress than copper of the same diameter. This also means that aluminum cables can bend more easily without kinking or snapping than copper cables.


2. Corrosion resistance

Another factor to consider is corrosion resistance, which measures how well a material can resist deterioration due to chemical reactions with air, water, or other substances. The higher the resistance, the longer a material lasts without losing its quality or functionality.

Corroded Surface on Cables
Corroded Surface

Aluminum has a higher corrosion resistance than copper, which means it lasts longer without deteriorating due to chemical reactions with air, water, or other substances than copper of the same diameter. This also means that aluminum cables require less maintenance and protection against corrosion than copper cables.


However, copper has a higher oxidation resistance than aluminum, which means it lasts longer without deteriorating due to exposure to oxygen in air than aluminum of the same diameter. This also means that copper cables require less maintenance and protection against oxidation than aluminum cables.



Cost-Effectiveness of Copper vs. Aluminum Solar Cables

Another factor to consider when choosing a solar cable material is its cost-effectiveness, which measures how much value you get for your money. The higher the cost-effectiveness, the more value you get for your money.

Get Value from Money
Get Value from Money

The cost-effectiveness of solar cable material depends on several factors, such as the price of the material, the efficiency of the cable, the installation and maintenance costs, and the lifespan of the cable.


1. Price of the Material


Aluminum solar cables are generally cheaper than copper cables, due to the lower price of aluminum and the simpler processing required to manufacture the cables. However, the lower efficiency and durability of aluminum cables can increase their operational cost in the long run, as they may require more maintenance and replacement.


2. Voltage Drop

Another factor that affects the cost-effectiveness of a solar cable material is its voltage drop, which measures how much voltage is lost along a cable due to its resistance. The lower the voltage drop, the less power loss and heat generation there is in a cable.


Copper solar cables have a lower voltage drop than aluminum cables, which means they lose less power and generate less heat than aluminum cables of the same diameter. This also means that copper cables can be longer than aluminum cables for a given voltage rating, which reduces their connection costs.


However, aluminum solar cables have a lower density than copper cables, which means they can carry more current per unit weight than copper cables of the same diameter. This also means that aluminum cables can be thicker than copper cables for a given current rating, which reduces their voltage drop.


With increasing cable size, the difference in voltage drop between copper and aluminum decreases while the cost of copper increases significantly. This indicates that aluminum has a strong cost advantage when a small voltage drop is required.



Environmental Impact of Copper vs. Aluminum Solar Cables

A Sustainable Future
A Sustainable Future

Another factor to consider when choosing a solar cable material is its environmental impact, which measures how much it affects the natural resources and ecosystems around it. The lower the impact, the more sustainable and eco-friendly material is.



Copper solar cables have a higher environmental impact than aluminum cables, because copper mining and processing consume more energy and water, emit more greenhouse gases, and generate more waste than aluminum mining and processing. Copper also has a higher scrap value than aluminum, making it more attractive to thieves who may damage or steal PV systems for profit.


Aluminum solar cables have a lower environmental impact than copper cables, because aluminum mining and processing consume less energy and water, emit fewer greenhouse gases, and generate less waste than copper mining and processing. Aluminum also has a lower scrap value than copper, making it less attractive to thieves who may damage or steal PV systems for profit.


However, both materials have some negative effects on the environment that should be minimized or mitigated by using recycled or renewable sources, implementing proper waste management practices, and following ethical standards for labor rights and safety.



How to Decide Which Solar Cable Material is Best for Your PV System

As you can see, there is no clear-cut answer to which solar cable material is better: copper or aluminum. Both materials have their pros and cons depending on various factors such as electrical conductivity, mechanical strength, corrosion resistance, thermal expansion coefficient, cost-effectiveness, environmental impact, etc.

Choose the Right PV Cable
Choose the Right PV Cable

TIPS:

  • If you want high efficiency, reliability, and durability for your PV system with minimal maintenance costs over time but don’t mind paying more upfront for your solar cables, then, choose copper.

  • If you want low upfront costs for your PV system with high flexibility and corrosion resistance but don’t mind sacrificing some efficiency reliability, and durability over time with higher maintenance costs then choose aluminum.

  • If you want both high-efficiency reliability, and durability as well as low upfront costs for your PV system but are willing to compromise on some flexibility corrosion resistance, and thermal stability then choose a combination of copper and aluminum solar cables.

However, if you choose to use a combination of copper and aluminum solar cables, you need to pay attention to the transition method when connecting them together or to other equipment with different terminals. If the method is incorrect, the cables could cause a catastrophic event due to galvanic corrosion, overheating, or fire1. Therefore, you need to use proper connectors, such as bimetallic lugs or compression joints, that can prevent contact between dissimilar metals and ensure a secure connection.



Conclusion

To make an informed decision, you need to consider your specific needs, preferences, and budget. You also need to consult with an expert installer who can advise you on the best practices for selecting, installing, and maintaining your solar cables.


FRCABLE is a well-trusted solar cable manufacturer in China which produce both copper and aluminum cables. If you want to learn more information or guidance on choosing copper or aluminum, please contact us today for a free consultation. You can also place a quote here.


I hope this blog post has helped you understand the differences between copper and aluminum solar cables and how to decide which one is best for your PV system. If you have any questions or comments, please feel free to leave them below. Thank you for reading!

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